Wednesday, March 14, 2012

Paddle Design - Prologue

I've had two different prototype paddles kicking around for a while that I was not able to get to the point where I liked them.  What I typically do when I build new paddle designs is to overbuild them and then whittle away at them until they work to my satisfaction, or at least until their performance does not improve any more. Sometimes, it is just not possible to rescue a paddle design.  I have to walk away from some paddles and simply write them off as a learning experience. I generally have no idea how a new paddle will work until I actually try it out.  I would like to say that the more paddles I build, the better I get at predicting paddle performance, but I would be lying.  The only way I can tell what design will work is to actually build it and try it out. 

I should also mention that a paddle must be matched to the boat as well as the paddler to perform well.  A paddle is not a good paddle in the abstract.  A paddle is a good paddle only for a specific set of conditions.  In this case, I happened to have my King Island kayak readily available and that became the test platform.  The King Island kayak was fairly well suited to this particular paddle test because the King Island kayak's high deck calls for long paddles and the set of paddles I was testing were fairly long, 98 inches.  I had already modified both paddles based on previous tests. One paddle had started out at 102 inches long and I cut it down and the other had a loom that was way too fat for comfortable use and I had slimmed down the loom on it.  The thing about the fat loom was that it felt good in the shop, but out on the water in action, it was just too bulky.
Here's a shot of the inside of the King Island kayak. Note the high deck ridge.  The thing about a high deck is that it forces you to hold the paddle up higher which means that it has to be longer to reach the water.
And here is a shot of the two test paddles on the deck of the kayak.  The lower paddle was based on a paddle shown in an old illustration. The upper paddle is a breakdown version of a more conventional Unangan shape except for the loom.

Both paddles are versions of an Unangan (Aleut) design. The Unangan paddles are asymmetrical with the loom offset from the plane of the blades. 
And so I had my test paddles, test boat and test pond, San Francisco Bay.  Even though I had whittled away at both paddles and tried to improve their feel, I preferred the one piece paddle because it was lighter and seemed to move the boat with less effort.  The breakdown paddle felt heavy and more ponderous in the water. 
After the initial test I did a little more whittling and then took out both paddles again and this time I had my GPS with me.  The GPS gives me a speed readout which I can use to measure top speed for a boat or paddle and if I have two or more paddles, it gives me top speed for comparative effort.  Effort expended is pretty much a subjective measure but on a given outing, swapping paddles back and forth several times gives me a pretty good idea of comparative efficiency of two paddles.
And this is where the GPS comes in.  Although one paddle may feel better than another the one that feels worse may actually be giving me a better top speed. It may feel worse because it moves more water and makes me work harder.  But if I am simply cruising, comfortable feel of a paddle may be more important than top speed. Comfortable feel may also be an indication of better efficiency of one paddle over another. 
So to sum up, paddle design for me is a pragmatic exercise.  I have to test paddles on the water to tell whether they are any good and results are often surprising.  In a future blog, I will get more specific on factors that make for a good match between paddler, boat and paddle.


Anonymous said...

Wolfgang, is that "lower" paddle one with an offset loom, so that the blades hit the water sooner? I've seen some writeups of Aleut paddles with that design and am curious as to whether it works better as proposed for long distances.

Wolfgang Brinck said...

Both of the paddles shown have an offset loom. If the paddle is shaped properly, you don't have to grip it tightly to keep it properly oriented as you pull it through the water. Having to grip your paddle tightly eats up energy and becomes difficult when you paddle long distances.